Use of highly accurate sensors almost certainly requires calibration data to be used in the associated electronics. These calibration data may reasonably be assumed to be different from one sensor to another due to manufacturing tolerances and other variations.
In aerospace applications, it is often a requirement for these data to be physically stored on the sensor itself, thereby enabling the data to be read automatically by the interfacing avionics. A benefit on such approach is that if the sensor is replaced, the system can read the new calibration data from the new sensor and continue to perform, meeting its accuracy requirements, with no additional manual process to associate the new sensor with its calibration data.
In systems using electronic sensors with embedded circuits, storing the calibration data is relatively simple and can be achieved using programmable devices such as erasable programmable read only memory (EPROM). However, where intrinsic safety and electromagnetic interference (EMI) considerations drive the use of optical sensors and fiber optic communication with the sensor, EPROM can no longer be used without reintroducing an electrical connection to the sensor, obviating the benefits of the optical device.